• Title/Summary/Keyword: Personal Dosimeter

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Domestic Intercomparison Study for the Performance of Personnel Dosimeters (개인선량계 성능의 국내 상호비교)

  • Kim, Jang-Lyul;Chang, Si-Young;Kim, Bong-Hwan
    • Journal of Radiation Protection and Research
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    • v.21 no.3
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    • pp.147-153
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    • 1996
  • The Korea Atomic Energy Research Institute(KAERI) conducted a intercomparison study for personnel dosimetry services in Korea to enhance the accuracy and precision of the dosimetry system. Nine types of dosimeters(6 TLD, 3 film badge) from 7 institutions took part in this intercomparison study. Each participant submitted 30 dosimeters including transit control for irradiations. Both TLDs and film badges were irradiated with Cs-137 gamma, Sr/Y-90 beta and 4 X-ray beams in ISO wide series. Four dosimeters were irradiated on phantom with same dose equivalent for each field category. The delivered dose equivalent was in the range of $0.1{\sim}10mSv$. The participants assessed the results of their dosimeter readings in terms of the ICRU operational quantities for personal monitoring, Hp(10) and Hp(0.07). Most participants except 1 dosimeter estimated the delivered dose equivalent with biases less than ${\pm}25%$ for Cs-137 and Sr/Y-90. But for X-rays, the biases exceeded ${\pm}35%$ in some cases bacause the dose evaluation algorithm was based on the ANSI N13.11 X-ray fields which are different from those given by ISO.

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Individual Doses to the Public after the Fukushima Nuclear Accident

  • Ishikawa, Tetsuo
    • Journal of Radiation Protection and Research
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    • v.45 no.2
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    • pp.53-68
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    • 2020
  • Background: International organizations such as the World Health Organization (WHO) and the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) reported public exposure doses due to radionuclides released in the Fukushima nuclear accident a few years after the event. However, the reported doses were generally overestimated due to conservative assumptions such as a longer stay in deliberate areas designated for evacuation than the actual stay. After these reports had been published, more realistic dose values were reported by Japanese scientists. Materials and Methods: The present paper reviews those reports, including the most recently published articles; and summarizes estimated effective doses (external and internal) and issues related to their estimation. Results and Discussion: External dose estimation can be categorized as taking two approaches-estimation from ambient dose rate and peoples' behavior patterns-and measurements using personal dosimeters. The former approach was useful for estimating external doses in an early stage after the accident. The first 4-month doses were less than 2 mSv for most (94%) study subjects. Later on, individual doses came to be monitored by personal dosimeter measurements. On the basis of these measurements, the estimated median annual external dose was reported to be < 1 mSv in 2011 for 22 municipalities of Fukushima Prefecture. Internal dose estimation also can be categorized as taking two approaches: estimation from whole-body counting and estimation from monitoring of environmental samples such as radioactivity concentrations in food and drinking water. According to results by the former approach, committed effective dose due to 134Cs and 137Cs could be less than 0.1 mSv for most residents including those from evacuated areas. Conclusion: Realistic doses estimated by Japanese scientists indicated that the doses reported by WHO and UNSCEAR were generally overestimated. Average values for the first-year effective doses for residents in two affected areas (Namie Town and Iitate Village) were not likely to reach 10 mSv, the lower end of the doses estimated by WHO.

Developement of Radiation Measuring System using Wireless Communication (무선통신을 이용한 방사선측정 시스템 개발)

  • Lee, Bong-Jae;Chang, Si-Young
    • Journal of Radiation Protection and Research
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    • v.20 no.2
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    • pp.85-95
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    • 1995
  • Radiation measuring system using wireless communication method with single channel has been diveloped and tested. In this system, radiation signals from GM tube are transformed into digital pulses in pulse processing circuit and modulated in FSK (frequency shift keying) circuit for digital communication and then wirelessly transmitted to a receiving unit. The digital pulses received are then demodulated in FSK circuit and converted into radiation dose/dose rate in the data acquisition unit to display on the screen of a personal computer. The performance of this system was evaluated by using both a pulse generator and a standard radiation source(Cs-137). In both cases, digital pulses with 5V were observed in pulse processing circuit without distortion of their shape through wireless communication system. The experimental results of radiation measurement by this system after several test-irradiation of GM detector to a standard radiation source(Cs-137), showed good agreement with irradiation dose rate within 10% difference, and proved that this system could be effectively utillized as radiation measuring instrument. It is expected that this wireless radiation measuring system developed for the first time in Korea, can be used as a radiation monitor as well as a personal dosimeter if we can further improve this system to adopt wireless multichannel communication system.

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Development of Wireless Real-Time Gas Detector System for Chemical Protection Performance Test of Personal Protective Equipment (화생방 보호의 성능평가를 위한 무선 실시간 가스 검출기 개발)

  • Kah, Dong-Ha
    • Journal of the Korea Institute of Military Science and Technology
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    • v.23 no.3
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    • pp.294-301
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    • 2020
  • Man-In-Simulant Test(MIST) provides a test method to evaluate chemical protective equipments such as protective garments, gloves, footwear and gas mask. The MIST chamber is built to control concentration of chemical vapor that has a activity space for two persons. Non-toxic methyl-salicylate(MeS) is used to simulate chemical agent vapor. We carried out to measure inward leakage MeS vapors by using passive adsorbent dosimeter(PAD) which are placed on the skin at specific locations of the body while man is activity according to the standard procedure in MIST chamber. But more time is required for PADs and there is concern of contamination in PADs by recovering after experiment. Therefore detector for measuring in real time is necessary. In order to analyze in real time the contamination of the personal protective equipment inside the chemical environment, we have developed a wireless real-time gas detector. The detector consists of 8 gas-sensors and 1 control-board. The control-board includes a CPU for processing a signal, a power supply unit for biasing the sensor and Bluetooth-chipset for transmission of signals to external PC. All signals from gas-sensors are converted into digital signals simultaneously in the control-board. These digital signals are stored in external PC via Bluetooth wireless communication. The experiment is performed by using protective equipment worn on manikin. The detector is mounted inside protective equipment which is capable of providing a real-time monitoring inward leakage MeS vapor. Developed detector is demonstrated the feasibility as real-time detector for MIST.

Noise Exposure Assessment in a Dental School

  • Choosong, Thitiworn;Kaimook, Wandee;Tantisarasart, Ratchada;Sooksamear, Puwanai;Chayaphum, Satith;Kongkamol, Chanon;Srisintorn, Wisarut;Phakthongsuk, Pitchaya
    • Safety and Health at Work
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    • v.2 no.4
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    • pp.348-354
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    • 2011
  • Objectives: This cross-sectional study was performed in the Dental School of Prince of Songkla University to ascertain noise exposure of dentists, dental assistants, and laboratory technicians. A noise spectral analysis was taken to illustrate the spectra of dental devices. Methods: A noise evaluation was performed to measure the noise level at dental clinics and one dental laboratory from May to December 2010. Noise spectral data of dental devices were taken during dental practices at the dental services clinic and at the dental laboratory. A noise dosimeter was set following the Occupational Safety and Health Administration criteria and then attached to the subjects' collar to record personal noise dose exposure during working periods. Results: The peaks of the noise spectrum of dental instruments were at 1,000, 4,000, and 8,000 Hz which depended on the type of instrument. The differences in working areas and job positions had an influence on the level of noise exposure (p < 0.01). Noise measurement in the personal hearing zone found that the laboratory technicians were exposed to the highest impulsive noise levels (137.1 dBC). The dentists and dental assistants who worked at a pedodontic clinic had the highest percent noise dose (4.60 ${\pm}$ 3.59%). In the working areas, the 8-hour time-weighted average of noise levels ranged between 49.7-58.1 dBA while the noisiest working area was the dental laboratory. Conclusion: Dental personnel are exposed to noise intensities lower than occupational exposure limits. Therefore, these dental personnel may not experience a noise-induced hearing loss.

Fabrication of $CaSO_4$ : Tm, $CaSO_4$ : Tm-PTFE TLD Radiation Sensors and Its Characteristics ($CaSO_4$ : Tm, $CaSO_4$ : Tm-PTFE TLD 소자의 제작과 특성에 관한 연구)

  • Park, Myeong-Hwan;Lee, Joon-Il
    • Journal of radiological science and technology
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    • v.16 no.1
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    • pp.107-115
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    • 1993
  • In this study, to develop highly sensitive radiation sensors, $CaSO_4$ : Tm phosphors and its disc-type TLD elements embedded PTFE(polytetrafluoroethylene) are fabricated. The highest sensitivity of $CaSO_4$ : Tm phosphors is obtained when phosphors have been doped with 0.5mol % Tm and sintered in atmosphere at $600^{\circ}C$ for two hours. Fabricated disc-type elements are made from a homogeneous mixture of phosphors and PTFE powder. They are first cold-pressed and then polymerized at $370^{\circ}C$ in air for one hour. The dose dependence of the prepared $CaSO_4$ : Tm TLD radiation sensors is linear within the range of $100{\mu}Gy{\sim}10Gy$ for X-rays and ${\gamma}-rays$. The response of $CaSO_4$ : Tm to 30keV X-rays is ten times higher than that of 1.25MeV $^{60}Co\;{\gamma}-rays$. The fading rate of the main peak is about 2% per a month. The spectral peaks of TL emission spectrum are at about 350nm and 475nm. The $CaSO_4$ : Tm TLD radiation sensors prepared in this work may be used as radiation dosimeter for personal and environmental monitoring because of their high sensitivity and little fading.

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Development of Algorithm for Evaluation of the Dose with Thermoluminescence Dosimeter (열형광선량계에 의한 선량평가 알고리즘 개발)

  • Song, Myung-Jae;Kim, Hee-Keun;Ha, Chung-Woo;Lee, Tae-Young;Yoon, Suk-Chul
    • Journal of Radiation Protection and Research
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    • v.17 no.2
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    • pp.1-13
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    • 1992
  • The purpose of this study is to develop an algorithm of TLD dose evaluation to meet all requirements stated in ANSI N13. 11-1983. It made the PB-3 TLD of Teledyne Isotopes an object of the development. Personal dosimetry performance testings of the development algorithm have been performed twice through the Atlan-Tech, INC. in accordance with the criteria of testing described in ANSI N13. 11-1983. As ,a result, it is assured that the developed algorithm has complied with all requirements stated in ANSI N13. 11-1983.

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GSTM1, GSTT1, and GSTP1 Gene Polymorphisms Modify the Effect of Smoking on Serum Immunoglobulin E Level

  • Kim, Jin-Hee;Kim, Yong-Kyu;Park, Shin-Gu;Choi, Ji-Ho;Kim, Cheol-Woo;Lee, Kwan-Hee;Ha, Eun-Hee;Hong, Yun-Chul
    • Molecular & Cellular Toxicology
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    • v.2 no.1
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    • pp.29-34
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    • 2006
  • Immunoglobulin E (IgE) plays an important role in the development of allergic disorders including asthma. Cigarette smoking was reported to elevate serum IgE level and air pollutants such as $NO_{2}$ have been reported to modulate the immune system including inflammation. Moreover, genetic polymorphisms of glutathione S-transferases (GSTs) were reported to affect inflammatory diseases including asthma. Therefore, in the present study we tried to investigate whether tobacco smoke or $NO_{2}$ exposure increases the level of IgE and the GST gene polymorphisms are associated with change of IgE level due to tobacco smoke or $NO_{2}$ exposure. We measured urinary cotinine, personal $NO_{2}$ exposure, and serum IgE levels in 300 healthy university students without allergic disorders. Allelic loss of the GSTM1 and GSTT1 and the GSTP1 (lle105Val) polymorphism were determined by PCR and RFLP. Total serum IgE levels were significantly different according to urinary cotinine levels (P=0.046), while $NO_{2}$ passive dosimeter level and genetic polymorphisms of three GSTs were not associated with total IgE level. Moreover, subjects with cotinine $500\;{\mu}g/g$ creatinine or more showed the highest level of total IgE when they had null type of GSTM1, null type of GSTT1, or variant type of GSTP1 (P<0.05). When we considered IgE level according to urinary cotinine levels in strata with the combinations of GSTM1, GSTT1, and GSTP1 genetic polymorphisms, the subjects with GSTM1 null, GSTT1 null, and GSTP1 variant types showed the largest difference between IgE levels of subpopulations according to cotinine levels (P=0.030). However, there was no significant difference between IgE levels of subpopulations according to $NO_{2}$ passive dosimeter levels in any group with combinations of GSTM1, GSTT1, and GSTP1 polymorphisms. This result suggests that smoking increases allergic response measured as IgE level and combinations of the GSTM1, GSTT1, and GSTP1 polymorph isms modify the effect of smoking on serum IgE level.

Developments of Space Radiation Dosimeter using Commercial Si Radiation Sensor (범용 실리콘 방사선 센서를 이용한 우주방사선 선량계 개발)

  • Jong-kyu Cheon;Sunghwan Kim
    • Journal of the Korean Society of Radiology
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    • v.17 no.3
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    • pp.367-373
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    • 2023
  • Aircrews and passengers are exposed to radiation from cosmic rays and secondary scattered rays generated by reactions with air or aircraft. For aircrews, radiation safety management is based on the exposure dose calculated using a space-weather environment simulation. However, the exposure dose varies depending on solar activity, altitude, flight path, etc., so measuring by route is more suggestive than the calculation. In this study, we developed an instrument to measure the cosmic radiation dose using a general-purpose Si sensor and a multichannel analyzer. The dose calculation applied the algorithm of CRaTER (Cosmic Ray Telescope for the Effects of Radiation), a space radiation measuring device of NASA. Energy and dose calibration was performed with Cs-137 662 keV gamma rays at a standard calibration facility, and good dose rate dependence was confirmed in the experimental range. Using the instrument, the dose was directly measured on the international line between Dubai and Incheon in May 2023, and it was similar to the result calculated by KREAM (Korean Radiation Exposure Assessment Model for Aviation Route Dose) within 12%. It was confirmed that the dose increased as the altitude and latitude increased, consistent with the calculation results by KREAM. Some limitations require more verification experiments. However, we confirmed it has sufficient utilization potential as a cost-effective measuring instrument for monitoring exposure dose inside or on personal aircraft.

Analysis of Trends in Dose through Evaluation of Spatial Dose Rate and Surface Contamination in Radiation-Controlled Area and Personal Exposed Dose of Radiation Worker at the Korea Institute of Radiological and Medical Sciences (KIRAMS)

  • Lee, Bu Hyung;Kim, Sung Ho;Kwon, Soo Il;Kim, Jae Seok;Kim, Gi-sub;Park, Min Seok;Park, Seungwoo;Jung, Haijo
    • Progress in Medical Physics
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    • v.27 no.3
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    • pp.146-155
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    • 2016
  • As the probability of exposure to radiation increases due to an increase in the use of radioisotopes and radiation generators, the importance of a radiation safety management field is being highlighted. We intend to help radiation workers with exposure management by identifying the degree of radiation exposure and contamination to determine an efficient method of radiation safety management. The personal exposure doses of the radiation workers at the Korea Institute of Radiological & Medical Sciences measured every quarter during a five-year period from Jan. 1, 2011 till Dec. 31, 2015 were analyzed using a TLD (thermoluminescence dosimeter). The spatial dose rates of radiation-controlled areas were measured using a portable radioscope, and the level of surface contamination was measured at weekly intervals using a piece of smear paper and a low background alpha/beta counter. Though the averages of the depth doses and the surface doses in 2012 increased from those in 2011 by about 14%, the averages were shown to have decreased every year after that. The exposure dose of 27 mSv in 2012 increased from that in 2011 in radiopharmaceutical laboratories and, in the case of the spatial dose rate, the rate of decrease in 2012 was shown to be similar to the annual trend of the whole institute. In the case of the surface contamination level, as the remaining radiation-controlled area with the exception of the I-131 treatment ward showed a low value less than $1.0kBq/m^2$, the annual trend of the I-131 treatment ward was shown to be similar to that of the entire institute. In conclusion, continuous attention should be paid to dose monitoring of the radiation-controlled areas where unsealed sources are handled and the workers therein.